Family Description

Terrestrial or epiphytic shrubs, subshrubs, perennial herbs, or fleshy achlorophyllous mycotrophs, sometimes lianoid, rarely trees, often rhizomatous; indumentum of uni- to multicellular hairs or scales, these sometimes glandular. Leaves alternate, rarely opposite, verticillate, whorled, or lacking and then replaced by bract-like scales, simple, usually petiolate, exstipulate, but rarely bud scales appearing pseudostipular; lamina coriaceous to membranous, evergreen to deciduous, the margin usually entire but sometimes serrulate-crenate, the venation pinnate or plinerved; leaf scars usually with a single vascular bundle scar, nodes usually with one trace and one gap. Inflorescence axillary or rarely terminal, racemose, paniculate, fasciculate, or flowers solitary; individual flowers pedicellate or rarely sessile in axils of small or large, deciduous or persistent, floral bracts; pedicel usually bibracteolate; bracteoles ususlly 2, persistent, small or large. Flowers mostly bisexual, but rarely functionally unisexual (more rarely plants dioecious), actinomorphic or slightly zygomorphic, mostly (3-) 5 (-7)-merous, typically obdiplostemonous, hypogynous or epigynous and with a typically biseriate perianth, typically without floral odors, rarely with extrafloral nectaries, with few exceptions the superior-ovaried genera pollinated by bees and the inferior-ovaried genera by hummingbirds (in Ecuador); aestivation valvate, imbricate, or reduplicate; calyx continuous or articulate with the pedicel, synsepalous, the sepals occasionally distinct, sometimes grading into bract-like scales, rarely fleshy and accrescent to the fruit, the hypanthium when present terete or angled to winged alternate with the lobes; corolla membranous to thick-carnose, polypetalous or more commonly sympetalous, cylindric, campanulate or urceolate, terete or angled to winged opposite the lobes; stamen (6-) 10 (-14), in 2 whorls, usually twice as many as the petals or rarely just as many, equalling the corolla in overall length or 1/2--1/3 the corolla length, equal with each other or alternately unequal, borne on the edge of an obscure to prominent nectariferous disc; filaments equal or unequal, usually straight or rarely S-shaped (geniculate), ligulate but sometimes basally dilated, sometimes also basally papillose, distinct or connate, with or without spurs, shorter or longer than the anther; anther inverting during development, 2-celled, equal or unequal, often distally with 2 distinct or connate tubules or terminal awns, sometimes provided with abaxial spurs; disintegration tissue present or lacking; thecae smooth to coarsely granular, the base rounded to apendiculate; tubules when present conical and rigid or cylindric and flexible, of equal or ca 1/2 the diameter of the thecae, longer to shorter than the thecae; dehiscence normally introrse, but rarely extrorse or latrorse, by longitudinal or more typically by apical to subapical clefts or pores; pollen grains in tetrahedral tetrads or rarely single, sometimes with viscin threads; pistil single; ovary superior or inferior, 4--5 (-10)-carpellate, usually with as many locules as carpels or with twice as many locules as carpels or rarely loculate in lower portion and 1-locular above; placentation axile, rarely intruded parietal; ovules numerous per locule or rarely solitary, anatropous to campylotropous with a single integumentary layer; style single, fluted, hollow; stigma simple but occasionally weakly lobed. Fruit a loculicidal or septicidal capsule, berry, or drupe, with a usually persistent, rarely accrescent and fleshy calyx; seeds small, ca 1--1.5 mm long, usually numerous (1 per locule in Gaylussacia ), winged or tailed (only in Bejaria ), sometimes enclosed in a mucilaginous sheath, the testa thin with elongated or isodiametric cells, the endosperm fleshy, the embryo straight, usually white or sometimes green.

The family comprises ca 110 genera with ca 4000 species, and is cosmopolitan with the exception of Antarctica. In Ecuador, 21 genera and 218 species are known at present. Rhododendron simsii Planchon is sometimes cultivated in the montane areas throughout the Neotropics. Two species, Macleania costeroides and M. cardiophylla, are of uncertain status.